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Key bindings
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<h3>Key bindings</h3>


<p>The association between a command and the key combinations that should
invoke the command is called a <b>key binding</b> Plug-ins can define key
bindings along with commands in the
<a href="../reference/extension-points/org_eclipse_ui_bindings.html">org.eclipse.ui.bindings</a>
extension point. From our InfoView example:</p>

<pre>
   &lt;extension
         point=&quot;org.eclipse.ui.bindings&quot;&gt;
      &lt;key
            commandId=&quot;org.eclipse.ui.examples.contributions.view.edit&quot;
            contextId=&quot;org.eclipse.ui.examples.contributions.view.context&quot;
            sequence=&quot;M1+O&quot;
            schemeId=&quot;org.eclipse.ui.examples.contributions.scheme&quot;&gt;
      &lt;/key&gt;
   &lt;/extension&gt;
</pre>


<p>The <b>sequence</b> attribute for a key binding defines the key
combination that is used to invoke a command. As long as our InfoView
context is active, we will try and execute the InfoView edit command when the
user chooses <b>CTRL+O</b> and the scheme is set to
<b>org.eclipse.ui.examples.contributions.scheme</b>.  The mapping of <b>M1</b> to <b>CTRL</b>
is described in the extension point description for
<a href="../reference/extension-points/org_eclipse_ui_bindings.html">org.eclipse.ui.bindings</a>.
</p>
<p>
The <b>contextId</b> indicates what active context this key binding will
be active in.  More information on defining contexts declaratively and
activating them programmatically can be found in 
<a href="workbench_advext_contexts.htm" 
   class="XRef">Contexts</a>.  In this case, this key binding will be active
when the <b>org.eclipse.ui.examples.contributions.view.context</b> context
is active.
</p>
<p>
In our InfoView we have code called from the end of createPartControl(Composite):</p>
<pre>
	private static final String VIEW_CONTEXT_ID = &quot;org.eclipse.ui.examples.contributions.view.context&quot;; //$NON-NLS-1$
	...
	/**
	 * Activate a context that this view uses. It will be tied to this view
	 * activation events and will be removed when the view is disposed.
	 */
	private void activateContext() {
		IContextService contextService = (IContextService) getSite()
				.getService(IContextService.class);
		contextService.activateContext(VIEW_CONTEXT_ID);
	}
</pre>

<p>
As mentioned in <a href="workbench_cmd_handlers.htm" 
   class="XRef">org.eclipse.ui.handlers</a> this context will be active
only when the InfoView part is active.  It will also be deactivated when
the InfoView part is disposed.
</p>

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